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Putting Waste to Work

Sarah P. Duke Gardens creates own compost for gardens

Lindsey Fleetwood, horticulturist with Sarah P. Duke Gardens, turns over a collection of compost. After it finishes degrading, the compost is used throughout the Gardens. Photo by Bryan Roth.
Lindsey Fleetwood, horticulturist with Sarah P. Duke Gardens, turns over a collection of compost. After it finishes degrading, the compost is used throughout the Gardens. Photo by Bryan Roth.

Sarah P. Duke Gardens has been doing some home “cooking” this summer but not necessarily with ingredients found in a kitchen.

Standing as tall as 5 feet, three piles of compost near the Charlotte Brody Discovery Garden have slow roasted at internal temperatures as high as about 150 degrees, spurred by summer sun. Garden trimmings, straw, eggshells and more compose the piles, each at different stages of decay, the heat eliminating weeds, seeds, harmful insects and disease pathogens.

As the compost rests within contained, concrete areas for three months, Duke Gardens employees locate spots throughout the Gardens’ 55 acres to use the organic material. Using compost provides plants in Duke Gardens with more nutrients for growth, strengthens soil structure and increases soil’s water retention.

“I’ve always done it on a small scale at home, but it’s also nice to be sustainable and follow best practices at work,” said Jason Holmes, curator for the Doris Duke Center Gardens. He developed and manages the composting program. “We have the equipment, people and biomass to do it, so we set it up and rely on Mother Nature to do the rest.”

Holmes estimates that last year, Duke Gardens created as much as 30 yards of compost, which was used in the Discovery Garden, Culberson Asiatic Arboretum and H.L. Blomquist Garden of Native Plants. The amount of compost created on-site not only provided fresh, organic compost for Gardens’ staff, but it also cut $3,000 to $5,000 that would’ve been spent on bringing in compost from an outside business.

For his work developing and maintaining the program, Holmes received a campus Sustainability Award in April for outstanding leadership in waste reduction. He was nominated by Bobby Mottern, director of horticulture at Duke Gardens, who noted that the mantra of “reduce, reuse, recycle” has become woven throughout many daily actions at Sarah P. Duke Gardens because of Holmes’ work.

“Having this compost program points us in the direction of sustainability which everybody is trying to strive for,” Mottern said. “When you buy products off the shelf, there may be other additives blended into them so you’re not sure what may exactly be in the compost. With this, it’s clean, reliable and we know where it came from start to end.”

In addition to the large compost piles at the Charlotte Brody Discovery Garden, Gardens volunteers also suggested Holmes start vermicomposting, the process of creating compost using worms. As many as 2,000 red wiggler worms in a 2-by-4 feet box chew through newspaper, lettuce, cardboard and other roughage to create high-nutrient compost for planters and raised beds throughout Duke Gardens.  

“You’re talking about all the material that normally would’ve been taken to some bin and you’d never see it again,” Holmes said. “With our composting, we see what goes in and what comes out. It’s like making an investment in the Gardens.”